More than a quarter-million Chinese students attending college in the United States saw their futures plunged into uncertainty Wednesday when the Trump administration announced an aggressive crackdown on student visa holders from that country. With an estimated 277,398 students pursuing primarily undergraduate and graduate degrees, China ranks only behind India among foreign countries with the highest number of students attending college in the U.S., according to data from the Institute of International Education. Since China’s middle-class boom in the early aughts, its students have flocked to U.S. institutions, which in turn welcomed the enrollment boost and mostly unsubsidized tuition fees....